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I have a 2022 Silverado 1500 2.7L with the 8 speed transmission. I have had is in to the dealer on multiple occasions for transmission issues. The hard downshift around 32-27 MPH, and shuddering around 59-61 MPH. The dealer has changed the transmission fluid (and flushed), and reprogrammed the TCM with the current code 18YN195646211. I have driven the truck over 600 miles and the shuddering around 59-61 MPH is no longer an issue. However the hard downshift around 32-27 MPH is still there and MORE IMPORTANTLY it feels as if my transmission is dragging or braking (slowing down truck). Whenever I lift my foot off the pedal over 30MPH and above, the truck instantly starts to slow down. It feels as if the brakes are on or that the transmission is in a lower gear like D2. I have driven the truck on flat ground and at 55 MPH lifted my foot off gas and placed truck in neutral, and within a second the truck starts to slowdown. FAST like there is no coast at all. I have tested this while going down hill at 60 MPH both in gear and in neutral and the same thing, it starts to slow down. Even going down hill. I have also noticed that the transmission makes a slight whine when I accelerate rapidly (not the turbo sound).

Any ideas or advice would be much appreciated. Is there an internal transmission brake or torque converter brake that is malfunctioning? My brakes are fine and new, they are not overheating or wearing down unevenly.
This started at 26000 miles and I am now at 31000 miles.

Thank you.